نتایج جستجو برای: bedload transport

تعداد نتایج: 273915  

2018
Sergio Maldonado Alistair G L Borthwick

We derive a two-layer depth-averaged model of sediment transport and morphological evolution for application to bedload-dominated problems. The near-bed transport region is represented by the lower (bedload) layer which has an arbitrarily constant, vanishing thickness (of approx. 10 times the sediment particle diameter), and whose average sediment concentration is free to vary. Sediment is allo...

2016
S. Schwindt

The design of open check dams at mountain rivers for flood protection has an essential impact on the sediment budget of downstream river reaches. A key issue is the bedload transfer hindering and retention which can be influenced by the geometry of the openings of check dams. Contemporary design concepts provoke the retention of too much or insufficient bedload with regard to the downstream tra...

2016
Kurt Imhoff Marco P. Maneta Andrew Wilcox

Sediment routing in gravel-bed rivers refers to the intermittent transport and storage of bedload particles, where short-duration steps are separated by periods of inactivity. Channel morphology governs sediment routing, but morphologic effects on routing in headwater systems are not well understood compared to lowland systems. RFID tracers are a valuable tool that can be employed to characteri...

2005
W. E. Dietrich P. A. Nelson E. Yager J. G. Venditti

Bed surface particle size patchiness may play a central role in bedload and morphologic response to changes in sediment supply in gravel-bed rivers. Here we test a 1-D model (from Parker ebook) of bedload transport, surface grain size, and channel profile with two previously published flume studies that documented bed surface response, and specifically patch development, to reduced sediment sup...

2017
Jose Ramon B. Cantalice Luis da Silva Souza Yuri Jacques Agra Bezerra Silva Sergio M.S. Guerra Alex Mauricio Araújo Douglas Monteiro Cavalcante Cinthia Maria Cordeiro Atanazio Cruz Silva

Sediment transport relates to suspended sediment and bedload. The suspended sedi‐ ment plays the most important role on the land-ocen sediment flux. On the other hand, the bedload should be considered in order to assess the impacts of dams on sediment transport and sediment yield. Recent effects of dam construction have been widely reported. The sediment load has been reduced by more than 75% f...

2016
Christian González David H. Richter Diogo Bolster Samuel Bateman Joseph Calantoni Cristián Escauriaza

At the smallest scales of sediment transport in rivers, the coherent structures of the turbulent boundary layer constitute the fundamental mechanisms of bedload transport, locally increasing the instantaneous hydrodynamic forces acting on sediment particles, and mobilizing them downstream. Near the critical threshold for initiating sediment motion, the interactions of the particles with these u...

2016
Raphael Maurin Julien Chauchat Philippe Frey

The local granular rheology is investigated numerically in turbulent bedload transport. Considering spherical particles, steady uniform configurations are simulated using a coupled fluid-discrete-element model. The stress tensor is computed as a function of the depth for a series of simulations varying the Shields number, the specific density and the particle diameter. The results are analyzed ...

2002
L. Collins

Bed surface particle size patchiness may play a central role in bedload and morphologic response to changes in sediment supply in gravel-bed rivers. Here we test a 1-D model (from Parker ebook) of bedload transport, surface grain size, and channel profile with two previously published flume studies that documented bed surface response, and specifically patch development, to reduced sediment sup...

Journal: :Environmental Fluid Mechanics 2014

Journal: :Journal of Hydraulic Engineering 2023

Numerous theories have been presented over the years for quantifying bedload transport in streams and rivers. These derived using physical processes, statistical methods, semiempirical empirical methods rely on a variety of hydraulic, boundary, bed material properties. Most these equations represent instantaneous related to temporal hydraulic conditions are not well-suited estimate long-term av...

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